Paper separation mechanism

ABSTRACT

A paper separation mechanism, comprising a separation roller assembly having a separation roller, a torque limiter connected to the separation roller, and a separation gear arranged between the separation roller and the torque limiter; a transmission gear assembly having a first transmission gear which is able to mesh or separate with the separation gear, a second transmission gear meshed with the first transmission gear, and a connecting part connected the first transmission gear and the second transmission gear; and a motor connected to the transmission gear assembly for applying forward or reverse torque; wherein when the motor is applying the forward torque, the connecting part rotates forward to mesh the first transmission gear with the separation gear; and when the motor is applying the reverse torque, the connecting part rotates reverse to separate the first transmission gear with the separation gear.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on, and claims priority from, Taiwan Patent Application No. 109202014, filed Feb. 24, 2020, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a paper separation mechanism, in particular to a paper separation mechanism of an automatic document feeder which provides a stable separation effect when single or multiple sheets of paper are fed.

2. The Related Art

In a conventional paper separation mechanism, the separation roller generates a separating force in cooperation with a torque limiter. The separating force is the rotating torque of the torque limiter divided by the radius of the separation roller, and with the separating force which is greater than the adhesion between paper and paper, the overlapped papers can be separated.

The conventional paper separation mechanism is designed into two types, the passive separation roller and the active separation roller. FIG. 4 shows a conventional passive design which comprises a separation roller 11′ and a torque limiter 111′ arranged with the separation roller 11′. While no additional torque is applied to the separation roller 11′, the separation roller 11′ is brought to rotate only by the documents that fed through. In this case, the only way to increase the separating force is increasing the torque of the torque limiter, and that may lead to a problem of uneven wear of the separation roller 11′.

FIG. 5 shows an active design which drives a torque limiter 111′ with a transmission gear assembly 2′ to rotate the separation roller 11′ in a direction in opposition to paper movement. The active separation roller 11′ avoids the problem of uneven wear in the same position, and further enhance the separating effect by transporting the multiple fed paper backward. However, because the separation roller 11′ rotates in the direction in opposition to the paper movement, it is prone to cause the leading edge of the paper to fold back.

Therefore, it is necessary to provide a paper separation mechanism which is able to avoid the leading edge of the paper to fold back, and provide greater separating force.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a separation mechanism which is able to avoid the leading edge of the paper to fold back, and provide greater separation force.

To achieve said objective, a paper separation mechanism, comprising a separation roller assembly having a separation roller, a torque limiter connected to the separation roller and a separation gear arranged between the separation roller and the torque limiter; a transmission gear assembly having a first transmission gear which is switched to mesh to the separation gear or switched to separate from the separation gear, a second transmission gear which meshes to the first transmission gear and a connecting part which connects the first transmission gear and the second transmission gear; and a motor connected to the transmission gear assembly for applying a torque in a forward or reverse direction to the transmission gear assembly; wherein when the motor is applying the torque in the forward direction, the connecting part rotates forward to mesh the first transmission gear with the separation gear; wherein when the motor is applying the torque in the reverse direction, the connecting part rotates reverse to separate the first transmission gear with the separation gear.

In a preferred embodiment, the transmission gear assembly has the first transmission gear which meshes with the separation gear to drive the separation gear, the second transmission gear which meshes with the first transmission gear, a third transmission gear which meshes with the second transmission gear, a fourth transmission gear which meshes with the third transmission gear, a fifth transmission gear which meshes with the fourth transmission gear and the motor, and the connecting part connects the first transmission gear and the second transmission gear.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be apparent to those skilled in the art by reading the following description, with reference to the attached drawings, in which:

FIG. 1 is a perspective view of a paper separation mechanism in this invention;

FIG. 2 is a perspective view of a first transmission gear meshing with a separation roller;

FIG. 3 is a perspective view of the first transmission gear separating from the separation roller;

FIG. 4 is a perspective view of a conventional passive paper separation mechanism;

FIG. 5 is a perspective view of a conventional active paper separation mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to explain in detail, the technical content, structural features, objectives and effects of the present invention, the following is a detailed description with reference to the drawings.

Referring to FIG. 1 to FIG. 3, a paper separation mechanism 100 in this invention is arranged in an automatic document feeder (not shown) for preventing multi-fed documents. The paper separation mechanism 100 includes a separation roller assembly 1, a transmission gear assembly 2 and a motor 3 for providing separating torque. For convenience of explanation, the terms “front” as used hereinafter refers to the direction in which the paper is fed toward as illustrated in FIG. 1.

The separation roller assembly 1 includes a separation roller 11 and a pick roller (not shown). The separation roller 11 connected to a torque limiter 111 which provides the separation roller 11 with a separating torque. A co-axial separation gear 112 is arranged between the separation roller 11 and the torque limiter 111.

Referring to FIG. 2 and FIG. 3, the transmission gear assembly 2 meshes with the motor 3 and has a first transmission gear 25 which is switched to mesh to the separation gear 112 or switched to separate from the separation gear 112. A second transmission gear 24 meshes to the first transmission gear 25 and connects to a connecting part 27 which connects the first transmission gear 25 and the second transmission gear 24. When the motor 3 is applying a torque in a forward direction (shown in FIG. 2), the connecting part 27 rotates forward to mesh the first transmission gear 25 with the separation gear 112. When the motor 3 is applying a torque in a reverse direction (shown in FIG. 3), the connecting part 27 rotates backward to separate the first transmission gear 25 from the separation gear 112.

In this embodiment, the transmission gear assembly 2 has the first transmission gear 25 which meshes with the separation gear 112 to drive the separation gear 112, the second transmission gear 24 which meshes with the first transmission gear 25, a third transmission gear 23 which meshes with the second transmission gear 24, a fourth transmission gear 22 which meshes with the third transmission gear 23, a fifth transmission gear 21 which meshes with the fourth transmission gear 22 and the motor 3, and the connecting part 27 which connects the first transmission gear 25 and the second transmission gear 24.

Referring to FIG. 1 and FIG. 2, the first transmission gear 25 and the second transmission gear 24 are linked by the connecting part 27. When the motor 3 is rotated counter-clockwise as shown in FIG. 2, it drives the intermeshed transmission gear assembly 2 to turn. A resistance between the connecting part 27 and the first transmission gear 25 causes the connecting part 27 to be brought to rotate counter-clockwise by the second transmission gear 24. Therefore the first transmission gear 25 is turned to engagewith the separation roller 112, thus the separation roller 11 is drove to rotate.

Referring to FIG. 1 and FIG. 3, When the motor 3 is rotated clockwise as shown in FIG. 3, it drives the intermeshed transmission gear assembly 2 to turn. The resistance between the connecting part 27 and the first transmission gear 25 causes the connecting part 27 to be brought to rotate clockwise by the second transmission gear 24. Therefore the first transmission gear 25 is turned to separate the first transmission gear 25 from the separation roller 112, thus additional resistance applied to the separation roller 11 is avoided.

In this embodiment, a damping oil is applied between the first transmission gear 25 and the connecting part 27 to increase the resistance between the first transmission gear 25 and the connecting part 27, enabling the first transmission gear 25 to turn the connecting part 27 as it turns.

The paper separation mechanism 100 in this invention is used to separate multi-fed documents. In the case of single-fed, the transmission gear assembly 2 is separated from the separation gear 112, in which case the paper separation mechanism 100 functions as a passive separation design In the case of multi-fed, the transmission gear assembly 2 is connected to the separation gear 112 by rotation of the motor 3 that drives the connecting part 27. So that the separation gear 112 bypass the torque limiter and receives the separation torque directly from the motor 3, and therefore the separation roller 11 is able to provide greater torque (aka greater separation force) for separating the documents without the limitation of the torque limiter 111. 

What is claimed is:
 1. A paper separation mechanism, comprising: a separation roller assembly having a separation roller, a torque limiter connected to the separation roller and a separation gear arranged between the separation roller and the torque limiter; a transmission gear assembly having a first transmission gear which is switched to mesh to the separation gear or switched to separate from the separation gear, a second transmission gear which meshes to the first transmission gear and a connecting part which connects the first transmission gear and the second transmission gear; and a motor connected to the transmission gear assembly for applying a torque in a forward or reverse direction to the transmission gear assembly; wherein when the motor is applying the torque in the forward direction, the connecting part rotates forward to mesh the first transmission gear with the separation gear; wherein when the motor is applying the torque in the reverse direction, the connecting part rotates reverse to separate the first transmission gear with the separation gear.
 2. The paper separation mechanism as claimed in claim 1, wherein the transmission gear assembly has the first transmission gear which meshes with the separation gear to drive the separation gear, the second transmission gear which meshes with the first transmission gear, a third transmission gear which meshes with the second transmission gear, a fourth transmission gear which meshes with the third transmission gear, a fifth transmission gear which meshes with the fourth transmission gear and the motor, and the connecting part connects the first transmission gear and the second transmission gear. 